Título del seminario de Alfonso F. Davila: How to search for a second genesis of life in the Solar System

Resumen: The number one goal in Astrobiology is to search for a second genesis of life beyond Earth. Contrary to what is commonly assumed, a second genesis of life cannot be inferred geographically; it can only be recognized based on ancestral biochemical qualities. Taking Terran life as the reference, we will explore the concept of a second genesis of life; how to look for it; and where to find it.

Resumen: Our understanding of long-term organic matter preservation comes mostly from studies in aquatic systems. In contrast, taphonomic processes in extremely dry environments are relatively understudied and are poorly understood. We investigated the accumulation and preservation of lipid biomarkers in hyperarid soils in the Yungay region of the Atacama Desert. Buried clay units with fossil organic matter (radiocarbon dead) that has been protected from rainwater since the onset of hyperaridity up to 2 million years ago were found to contain lipids in an excellent state of structural preservation with functional groups and unsaturated bonds in carbon chains. This indicates that minimal degradation of lipids has occurred in these soils since the time of their deposition between >40,000 and 2 million years ago. Our results suggest that hyperarid environments could represent a rich and relatively unexplored source of paleobiological information on Earth, and potentially Mars.

Título del seminario de Carol Stoker: Searching for life on early Mars: Lessons from the Pilbara

Resumen: Stromatolites in the Pilbarra region of western Australia constitute some of the earliest evidence of life on Earth, and the best evidence that is exposed in surface deposits. This talk discusses lessons from the search for evidence of life in the Pilbarra samples which suggests that evidence for early life on Mars is unlikely to be found by robotic rovers even with samples returned to Earth.